1. Field of the Invention
The present invention relates generally to thermal sensors, and more particularly to a thermal sensor system that determines a current ratio through one or more thermal sensors for measuring temperature.
2. Description of the Related Art
Conventional thermal (or temperature) sensors may rely upon the thermal coefficient of resistance requiring per-part calibration. Some sensors sense the analog voltage difference between 2 sensors at a fixed current as a metric for temperature variability. Most sensors rely on PTAT (proportional to absolute temperature) voltage relationships, whereas others rely on PTAT and CTAT (complementary to absolute temperature) comparisons. Accurate thermal monitoring usually requires either large area circuitry and/or the use of fabrication-enabled calibration of analog components (i.e. trimming or fuse controls). These solutions tend to be costly, either in terms of needing significant die area or requiring significant additional support (e.g., test, PE, bringup, etc.). It is also desired to accurately measure temperature within a large temperature range.